1. Field of the Invention
The present invention relates to a segment adapted for use for a rehabilitating pipe that is assembled to rehabilitate an existing pipe, such as a sewer pipe.
2. Description of the Prior Art
A method of rehabilitating an existing pipe is known from Japanese Patent Laid Open Publication No. 2003-214098 and the like, wherein a compound pipe is constructed to rehabilitate an existing pipe like a sewer pipe by, as shown in FIG. 11, assembling inside an existing pipe 4 a rehabilitating pipe 3 whose outer diameter is slightly less than the inner diameter of the existing pipe 4, and then filling and hardening a filler (not shown) in the gap between the outer periphery of the rehabilitating pipe 3 and the inside wall surface of the existing pipe 4. The rehabilitating pipe 3 is assembled using segments. Namely, as shown in FIG. 12, the rehabilitating pipe 3 is assembled by an assembly worker S who couples inside a manhole 5 in communication with the existing pipe 4 the arcuate segments 1 in the circumferential direction thereof (the circumferential direction of the rehabilitating pipe 3) to assemble a short, ring-shaped pipe unit 2 and then mutually coupling the pipe units 2 inside the existing pipe in the longitudinal direction of the pipe units 2 (the longitudinal direction of the rehabilitating pipe 3).
FIG. 13 shows a cross-section taken along the width direction (the longitudinal direction of the rehabilitating pipe) of a conventional segment 1. In FIG. 13, side plates 202 and 203 are provided upright on both sides in the width direction of an inner plate 201, whose bottom surface forms an inner circumferential surface of the rehabilitating pipe. V-shaped protruding parts 202a and rectangular recessed parts 203a are formed at two locations of an outer surface of the side plates, extending in the circumferential direction of the rehabilitating pipe. The segments 1 are coupled in the longitudinal direction of the rehabilitating pipe as shown in FIG. 14 by mutually coupling the pipe units 2; at that time, a sealing material (not shown) is coated inside the recessed parts 203a of the side plate 203 of one of the segments 1, and the protruding parts 202a of the side plate 202 of another of the segments 1 is fitted into those recessed parts 203a, and the outer surfaces of the side plate s202 and 203 are thereby mutually coupled so that their coupling surfaces make tight contact. Such a structure obtains watertightness in the coupling part of the rehabilitating pipe in the longitudinal direction. Furthermore, a similar structure obtains watertightness in the coupling part of the segments in the circumferential direction of the rehabilitating pipe.
Nevertheless, in the structure of the conventional segment 1 as described above, there is a problem in that watertightness can sometimes not be ensured in the coupling part because, in the state wherein the segments 1 are mutually coupled by fitting the protruding parts 202a to the recessed parts 203a as described above, the vertex part of the V shape of the protruding parts 202a only make line contact at the back flat surface of the recessed part 203a, and gaps occur between them due to the small contact surface between them.
It is therefore an object of the invention to provide a rehabilitating pipe segment that can improve the water tightness in the coupling part of mutually coupled segments.